1. Field of the Invention
The present invention relates to an absorbent article, such as disposable diaper, incontinence pad, in which a backing sheet is formed with continuous filaments.
2. Description of the Related Art
Absorbent article, such as disposable diaper, incontinence pad (urine-absorbing pad) and so forth is provided with a liquid permeable surface sheet on an inner surface of an absorbent layer and a liquid impermeable backing sheet on an outer surface.
The backing sheet is required a function for shutting off a liquid and is desired to have moisture permeability (air permeability) for reducing stuffy (frowst) feeling on a wearer. In the conventional disposable diaper, a moisture permeable (air permeable) film formed by forming fine air holes in a polyolefin type resin film, is used as the backing sheet.
However, the backing sheet formed of the resin film provides stiff contact feeling to the touch. Moreover, it degrades external appearance. In order to deal with this problem, there has been known a disposable diaper in which a non-woven fabric is provided to appear on the outer surface of the disposable diaper to thereby provide cloth-like contact feeling and external appearance.
For example, such a backing sheet employing a non-woven fabric is prepared by stacking a non-woven fabric on the outer surface of a liquid impermeable resin film and by fixing the resin film and the non-woven fabric substantially over the entire confronting faces or partially by hot melt type adhesive. In another method, it is prepared by extruding a molten resin onto one surface of a non-woven fabric for lamination to thereby integrate a resin film on the non-woven fabric.
However, the backing sheet in which the resin film and the non-woven fabric are adhesive bonded, becomes stiff as a whole, because fibers of the non-woven fabric are constrained as bonded with the resin film. This results in degradation of fit to the wearer""s body and feeling to the touch. On the other hand, the backing sheet in which the molten resin is laminated on the non-woven fabric, becomes further stiff, because the entire surface of the non-woven fabric is constrained by the resin film.
In addition, since the non-woven fabric is manufactured by bonding staple fibers to lower freedom of movement of individual fibers, soft feeling on the surface is restricted to lower texture. Moreover, ends of the fibers inherently appear on the surface of the non-woven fabric to degrade feeling to the touch.
Furthermore, the backing sheet having the non-woven fabric on the resin film requires bonding process or lamination process in manufacturing, large scale manufacturing facility is required to cause high manufacturing cost.
The present invention has been worked out in view of the shortcoming in the prior art as set forth above. It is an object of the present invention to provide an absorbent article using a backing sheet easy to manufacture, with high bulkiness for soft feeling and with the outer surface providing good feeling to the touch.
According to the invention, there is disclosed an absorbent article comprising:
a liquid permeable surface sheet;
a backing sheet;
an absorbent layer located between the surface sheet and the backing sheet;
the backing sheet including a liquid impermeable base sheet and a layer of continuous filaments individually extending along a longitudinal direction of the absorbent article and stacked on an outer surface of the base sheet, and the base sheet and the continuous filament layer being partially fixed.
Preferably, the base sheet and the continuous filament layer are fixed with each other at a plurality of fixing lines extending in a direction traversing the continuous filaments and spaced apart in a direction along which the continuous filaments extend. In this case, for example, the fixing line is in wave shaped pattern.
According to the invention, since the outer surface of the backing sheet is formed of the continuous filaments, the backing sheet becomes so bulky as to provide satisfactory cushioning ability. Especially since the continuous filaments extend continuously in the backing sheet, no fiber end appears on the outer surface of the backing sheet. Therefore, the outer surface of the backing sheet becomes so smooth. These continuous filaments can be prevented from falling out of the base sheet merely by partially fixing (bonding) them to the base sheet at fixing lines or the like. Therefore, fixing area (bond area) for the continuous filaments can be minimized to make the overall backing sheet soft. In the case where the base sheet is moisture permeable (air permeable), moreover, the continuous filament layer does not inhibit moisture permeability.
The absorbent article may be constructed such that the absorbent article has an intermediate portion for confronting a crotch portion of a wearer, a front portion for confronting an abdominal portion of a wearer and a rear portion for confronting a hip portion of a wearer, and that the rear portion is provided on laterally opposite side portions thereof with fasteners having engaging projections for engaging with the continuous filament layer in the front portion. In this case, bulkiness of the continuous filament layer is preferably increased at a region to which the fastener is intended to be engaged.
Moreover, the continuous filaments may be colored.